1. Field of the Invention
This invention relates generally to improvements in brakes for vehicles, and more particularly, to a braking means for preventing one wheel spin-out of automotive drive wheels. The invention is particularly concerned with an apparatus for alternately braking the drive wheels of an automotive vehicle by providing controlled separate braking on each of said wheels. The apparatus of the present invention is useful when an automotive vehicle having the usual two drive wheels is provided with the conventional type differential and is in a situation where one wheel slips and the other is on firm ground. The apparatus of the present invention in such situation is operative to apply the brakes on the usual two drive wheels in an alternate fashion, to permit the drive wheels to drive alternately, and thus move the vehicle out of a stuck position in mud, snow or the like.
2. Description of the Prior Art
It is well known in the automotive vehicle art to provide positive traction of both drive wheels by the use of limited slip differentials. However, such limited slip differentials must be built into the vehicle when it is manufactured in order to provide such a differential at minimum cost. It is not possible to install a limited slip differential on an automobile after it has been purchased without paying an exorbitant price. Also, limited slip differentials are not available on many vehicle models as original equipment or as after-market equipment.
Heretofore, other types of devices were built into a vehicle when it was manufactured, which would assist in applying a braking action to one rear drive wheel at a time, to facilitate the vehicle in pulling itself out of a slippery or skidding spot. One example of a device of this type is a special emergency brake shown in U.S. Pat. No. 2,433,581. The braking device shown in this patent is hand operated and is operated through the usual emergency brake lever. The brake handle for operating this device is located in a vehicle under the dashboard. Prior U.S. Pat. Nos. 1,635,727 and 1,736,082 each disclose mechanical means for alternately braking the rear wheels of a vehicle by means of hand operated levers mounted on the frame of the vehicle. Prior U.S. Pat. 1,584,358 and 2,821,265 disclose tow mechanically operated apparatuses for alternately braking the rear wheels of a vehicle, and wherein the apparatus is operated by foot pedals. U.S. Pat. No. 3,398,813 shows a similar mechanical device which is operated by hand knobs mounted on the dashboard of a vehicle. Prior U.S. Pat. Nos. 2,346,175, 2,351,098 and 3,466,096 each show hydraulic braking means for selective braking of the rear wheels of a vehicle.
None of the aforementioned prior art patents show a braking system for alternately braking the two drive wheels of an automotive vehicle by employing the regular emergency brake system, together with an easily attached oscillator means.